Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/99921
Citations
Scopus Web of Science® Altmetric
?
?
Type: Journal article
Title: Lack of sex chromosome specific meiotic silencing in platypus reveals origin of MSCI in therian mammals
Author: Daish, T.
Casey, A.
Grutzner, F.
Citation: BMC Biology, 2015; 13(1):106-1-106-13
Publisher: BioMed Central
Issue Date: 2015
ISSN: 1741-7007
1741-7007
Statement of
Responsibility: 
Tasman J. Daish, Aaron E. Casey and Frank Grutzner
Abstract: Background: In therian mammals heteromorphic sex chromosomes are subject to meiotic sex chromosome inactivation (MSCI) during meiotic prophase I while the autosomes maintain transcriptional activity. The evolution of this sex chromosome silencing is thought to result in retroposition of genes required in spermatogenesis from the sex chromosomes to autosomes. In birds sex chromosome specific silencing appears to be absent and global transcriptional reductions occur through pachytene and sex chromosome-derived autosomal retrogenes are lacking. Egg laying monotremes are the most basal mammalian lineage, feature a complex and highly differentiated XY sex chromosome system with homology to the avian sex chromosomes, and also lack autosomal retrogenes. In order to delineate the point of origin of sex chromosome specific silencing in mammals we investigated whether MSCI exists in platypus. Results: Our results show that platypus sex chromosomes display only partial or transient colocalisation with a repressive histone variant linked to therian sex chromosome silencing and surprisingly lack a hallmark MSCI epigenetic signature present in other mammals. Remarkably, platypus instead feature an avian like period of general low level transcription through prophase I with the sex chromosomes and the future mammalian X maintaining association with a nucleolus-like structure. Conclusions: Our work demonstrates for the first time that in mammals meiotic silencing of sex chromosomes evolved after the divergence of monotremes presumably as a result of the differentiation of the therian XY sex chromosomes. We provide a novel evolutionary scenario on how the future therian X chromosome commenced the trajectory toward MSCI.
Keywords: Sex Chromosomes; Animals; Platypus; Immunohistochemistry; In Situ Hybridization, Fluorescence; Gene Expression Profiling; Evolution, Molecular; Meiotic Prophase I; Meiosis; Epigenesis, Genetic; Gene Silencing; Male
Rights: © 2015 Daish et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
RMID: 0030049646
DOI: 10.1186/s12915-015-0215-4
Appears in Collections:Molecular and Biomedical Science publications

Files in This Item:
File Description SizeFormat 
hdl_99921.pdfPublished version3.76 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.